What inspections require an Exhaust Gas Recirculation (EGR) functional test?

• A. All 1995 and older ASM inspections require an EGR functional test.
• B. All vehicles require EGR test.
• C. Only diesel vehicles require EGR test.
• D. None require EGR test.

Answer: (A)

Exhaust Gas Recirculation helps lower NOx by recirculating a portion of exhaust back into the intake. In the California smog inspection system, the EGR functional test was used to verify that the EGR valve actually opens and allows proper flow when commanded, ensuring the system is working on vehicles where older mechanical/vacuum controls were common. This test was required for inspections of vehicles up to the 1995 model year because those cars typically relied on these non-OBD systems. Starting with later years, onboard diagnostics (OBD) monitor EGR performance, so a separate mechanical EGR test isn’t required for most modern vehicles. Hence, inspections for 1995 and older vehicles require the EGR functional test. The other options don’t fit because newer vehicles rely on diagnostics rather than a separate EGR test, EGR testing isn’t limited to diesels, and some older inspections did include it.